that would be a very hard task. Also, it depends on what breed you are training and doesn't just depend on how you treat it but how its mother and siblings did too. This decides how dominant/submissive the dog will be later on in life. Even the best guard dog breeds have strong personalities and it takes so much effort to train them.
To guard what and against what? I suggest an alarm system and signing up with the neighbourhood watch. Guard dogs often get poisoned so that people can break in. A dog is your companion, not your protector.
.....unfortunatly its better to pay the big bucks and get a trainer......but if you dont want a trainer handling your dog you could see about like, hands on lessons or whatever